NearPM: A Near-Data Processing System for Storage-Class Applications

Persistent Memory (PM) technologies enable both fast memory access and recovery in case of a failure. To ensure crash-consistent behavior, programs need to enforce persist ordering and employ mechanisms that introduce additional data movements such as logging, checkpointing, and shadow-paging. The emerging near-data processing (NDP) architectures can effectively reduce this overhead. In this work, we propose NearPM, a near-data processor that accelerates common, primitive operations that are crucial to crash consistency. Using these primitives, NearPM accelerates commonly-used crash-consistency mechanisms. NearPM further reduces the synchronization overheads between the NDP and the CPU by handling ordering near memory. We propose Partitioned Persist Ordering (PPO) that ensures a correct persist ordering between CPU and NDP devices, as well as among multiple NDP devices. We prototype NearPM on an FPGA platform. NearPM executes the data-intensive operations of crash-consistency mechanisms with correct ordering guarantees, while the rest of the program runs on the CPU. We evaluate nine PM workloads, each implemented in three crash consistency mechanisms: logging, checkpointing, and shadow paging. Overall, NearPM achieves 4.3 -- 9.8× speedup in the NDP-offloaded operations and 1.22 -- 1.35× speedup in the whole applications.